• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.312-316
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• 2004

The paper presents a technique to identify the boundary of the optic disc in infant retinal digital images using an approach based on active contours (snakes). The technique can be used to be develop a automate system in order to help the ophthalmologist's diagnosis the retinopathy of prematurity (ROP) disease which may occurred on preterm infant,. The optic disc detection is one of the fundamental step which could help to create an automate diagnose system for the doctors we use a new kind of active contour (snake) method has been developed by Chenyang et. al. [1], based on a new type of external force field, called gradient vector flow, or GVF. GVF is computed as a diffusion of the gradient vectors of a gray-level or binary edge map derived from the image. The testing results on a set of infant retinal ROP images verify the effectiveness of the proposed methods. We show that GVF has a large capture range and it's able to move snakes into boundary concavities of optic disc and finally the optic disk boundary was determined.

• 한국약용작물학회지
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• 제20권5호
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• pp.308-314
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• 2012

This study was carried out to investigate the antibacterial activity against pathogens of acne and the anti-inflammatory effect of 75% ethanol extract and its fractions from the leaves of Prunus sargentii. In the antibacterial activity by the disc diffusion assay, the extract showed the highest effect against Propionibacterium acnes, Staphylococcus aureus and Staphylococcus epidermidis in 5 mg/disc. However, the ethyl acetate fraction showed the highest antibacterial activity in 1 mg/disc. On the other hand, the hexane and chloroform fraction showed strong nitric oxide (NO) production inhibitory effect in lipopolysaccharide (LPS)-stimulated Raw 264.7 cell. In the cell viability of Raw 264.7 by MTT assay, the extract and all fractions were exhibited normal viabilities as nontoxic result. Consequently, the extract from the leaves of P. sargentii and its ethyl acetate fraction could be applicable to functional materials for antibacterial activity related fields. Moreover, the hexane and chloroform fraction could be applicable to candidate materials as anti-inflammatory agent.

• 한국식품조리과학회지
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• 제28권1호
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• pp.9-15
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• 2012

This study analyzed the antibacterial activity of a Rubus coreanum (Bokbunja) ethanol extract. The antimicrobial activity was determined by disc diffusion, minimum inhibitory concentration (MIC), and growth inhibition methods with seven kinds of bacteria related to foodborne illness (Bacillus cereus, Escherichia coli, Escherichia coli O157:H7, Listeria monocytogenes, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella typhimurium). In the results, disc diffusions of the ethanol extract from R. coreanum (9.8-17.5 mm at $4,000{\mu}g/disc$) clearly showed the antimicrobial activity of the extract against all tested microorganisms. Rubus coreanum promoted an inhibitory effect as follows: E. coli O157:H7 > P. aeruginosa > L. monocytogenes > E. coli > S. aureus > B. cereus ${\geq}$ S. typhimurium. In the MIC test, R. coreanum showed high antimicrobial effect against L. monocytogenes at 500 ppm. Moreover, the R. coreanum ethanol extract showed strong growth inhibition against microorganisms, similar to the MIC results. These results show that a R. coreanum ethanol extract has powerful antimicrobial activity against all tested microorganisms, suggesting that R. coreanum will be useful as a potential natural preservative.

• Journal of Applied Biological Chemistry
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• 제43권1호
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• pp.54-58
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• 2000

Methanol extracts of 27 Brazilian plant samples and 10 oriental medicinal plant samples (27 families), using spectrophotometric and paper disc agar diffusion methods under anaerobic conditions, were tested in vitro for their growth-inhibiting activities against Bifidobacterium longum, Bifidobacterium bifidum, Bifidobacterium adolescentis, Clostridium perfringens, and Bacteroides fragilis. The responses varied with bacterial strains, plant species, and tissues sampled. In a test with B. longum and B. bifidum(20 mg/disc), extracts of Acanthopanax sessilifolinus stem bark and Ampelozizyphus amazonicus leaves strongly inhibited the growth of B. longum, whereas other plant samples did not inhibit any intestinal bacteria tested. At 5 mg/disc, adding extracts of Aralia eleta, Euterpe oleracea, and Syzygium guineense to the media strongly inhibited the growth of C. perfringens and B. fragilis without growth inhibition of B. adolescentis, B. longum, and B. bifidum. Extracts of Jacaranda mimosifolia and Ulmus paraifolia significantly inhibited the growth of C. perfringens and B. fragilis as well as B. adolescentis. These results may be indications of at least one of the pharmacological actions of the five Brazilian plants but not oriental medicinal plants tested.

• 한국정밀공학회지
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• 제15권2호
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• pp.28-34
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• 1998

Powder metallurgy processes are able to form Net-Shape products and have been widely used in the production of automobile parts to improve its productivity. However, because of pores in powder products, the toughness of powder products are generally poor. Therefore, forged products are used in parts which suffer severe fatigue loads. In this paper, the choice of powder materials and production processes such as mixing, compaction, sintering, heat treatment to produce automobile spline hub are studied. Three type of materials are selected and processed and its microstructure and properties are investigated by tensile test, compression ring test, and impact test. Materials and processing methods are selected from the results. Finally, experimental spline hubs are manufactured by selected processes from selected powders and proved by torsional durability test.

• Advances in Traditional Medicine
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• 제8권1호
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• pp.47-52
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• 2008

The plant Eclipta prostrata, a member of the Compositae family, has folkloric reputation of being used as a medicinal agent in Bangladesh. In the present investigation, attempt was taken to explore the antimicrobial potency and cytotoxicity of its extractives and purified compounds. The methanolic extract of the whole plant, its n-hexane, carbon tetrachloride, chloroform, aqueous soluble fractions and two purified compounds, eclalbasaponin I (1) and II (2), obtained from Eclipta prostrata were subjected to screening for inhibition of microbial growth by the disc diffusion method at 300 and 100 ${\mu}g$/disc for extracts and pure compounds, respectively. In this case, the carbon tetrachloride and chloroform soluble fractions of the methanolic extract appeared very potent in terms of both zone of inhibition and spectrum of activity. However, all the extractives were also subjected to brine shrimp lethality bioassay for preliminary cytotoxicity evaluation. Here, the carbon tetrachloride soluble fraction of methanolic extract revealed the strongest cytotoxicity having $LC_{50}$ of 1.318 ${\mu}g$/ml.

• Journal of the Korean Wood Science and Technology
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• 제35권2호
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• pp.29-38
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• 2007

This study was undertaken to investigate the variation of equilibrium moisture content (EMC) in transverse direction and three different directional (longitudinal, radial, and tangential) linear movements, and diffusion coefficients within a tree disc of Korean red pine (pinus densiflora). The EMC gradually increased in heartwood from pith. Therefore, the chemical components might differ even in heartwood and the radial variation in EMC might have a close relationship with the cellulose content within a cross section. The specific gravity increases gradually from pith and the porosity has not direct influence on the variation of EMC within a tree disk. Both the radial and tangential diffusion coefficients exhibited clear trend of increase from pith. The EMC change (${\Delta}EMC$) and tangential diffusion coefficient were close to be axisymmetrical but others were deviated from axisymmetry. The diffusion coefficient decreases with decreasing an activation energy and specific gravity, The diffusion coefficient increased with increasing ${\Delta}EMC$ and hygroscopicity of wood might be inversely proportional to the activation energy, The fJEMC may depend on the chemical constituents of cellulose, hemicellulose and lignin. As the number of sorption sites and sorption capacity of wood increase, therefore, it might be assumed that the hygroscopicity of wood increases while activation energy decreases. Modeling physico-mechanical behavior of wood, the variations should be considered to improve the accuracy.

• 한국미생물·생명공학회지
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• 제42권4호
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• pp.361-366
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• 2014

본 연구에서는 다양한 추출조건에서 원산지별 감초(한국은 제천감초, 우즈베키스탄산, 중국산) 추출물의 피부 상재균에 대한 항균활성을 확인하였다. 원산지별 감초추출물의 추출조건은 추출용매(30% EtOH, 85% EtOH), 온도($40^{\circ}C$, $60^{\circ}C$), 시간(6 h, 12 h)을 조절하여 총 8군으로 설정하였다. 피부 상재균에 대한 항균활성은 disc diffusion assay, broth macrodilution assay 및 kill time curve assay에 의해 평가되었다. 각각의 조건별 추출물들에 대하여 disc diffusion assay에 의해 각 원산지별 항균활성을 확인한 후, 가장 우수한 항균활성을 보인 추출 조건을 선정하였다. 한국산 감초추출물(85% EtOH, $40^{\circ}C$, 12 h)이 가장 우수한 항균활성을 보였으며, 특히 P. acnes에 대하여 2.5 mg/disc에서 19 mm을 저해하였다. 최소저해농도(MIC)와 최소사멸농도(MBC)는 액체 희석법을 이용하였으며, 원산지별 감초추출물의 MIC와 MBC는 한국산 감초추출물에서 각각 $156{\mu}g/ml$과 $1,250{\mu}g/ml$로 우즈베키스탄 감초추출물($625{\mu}g/ml$과 $2,500{\mu}g/ml$)과 중국산 감초추출물($625{\mu}g/ml$과 $5,000{\mu}g/ml$)보다 가장 우수한 항균 활성을 나타내었다. 이상의 결과들을 통하여 다양한 추출조건에서 추출한 원산지별 감초추출물 중에서 가장 우수한 항균활성을 나타내는 최적의 조건과 원산지가 F군(85% EtOH, $40^{\circ}C$, 12 h)에서 추출한 한국산 감초임을 확인했다. 이는 현재 사용되는 합성 방부제를 대신할 천연방부제인 화장품 원료로서 응용 가능성이 있음을 시사한다.

• Journal of Korean Neurosurgical Society
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• 제63권1호
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• pp.45-55
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• 2020

Objective : Fibrin sealants have been used for hemostasis, sealant for cerebrospinal fluid leakage, and adhesive barrier in neurosurgery. Further, as its clinical use and role of an effective drug delivery vehicle have been proposed. This study was performed to measure antibacterial activity and continuous local antibiotic release from different concentrations of vancomycin-impregnated fibrin sealant in vitro. Methods : Antibacterial activity was investigated by disk diffusion test by measuring the diameter of the growth inhibition zone of bacteria (methicillin-resistant Staphylococcus aureus, ATCC29213) from vancomycin-embedded fibrin sealant disc diluted at five different concentrations (C1-C5; 8.33, 4.167, 0.83, 0.083, and 0.0083 mg/disc, respectively). Continuous and conditioned release of vancomycin concentration (for 2 weeks and for 5 days, respectively) were also measured using high-performance liquid chromatography (HPLC) method. To mimic the physiologic wound conditions with in vitro, conditioned vancomycin release in phosphate buffer solution (PBS) was measured and replaced PBS for five consecutive days, half a day or completely daily. Results : In the disk diffusion test, the mean diameters of bacterial inhibition zone were 2.54±0.07 cm, 2.61±0.12 cm, and 2.13±0.15 cm (C1, C2, and C3 respectively) but 1.67±0.06 cm and 1.23±0.15 cm in C4 and C5, respectively. Continuous elution test elicited the peak release of vancomycin from the fibrin sealant at 48 hours, with continued release until 2 weeks. However, conditioned vancomycin release decreased to half or more on day 2, however, the sustainable release was measured over the therapeutic dose (10-20 ㎍/mL) for 5 days and 4 days in assays of half and total exchange of PBS. Conclusion : This study suggests that fibrin sealant can provide an efficient vehicle for antibiotic drug release in a wide range of neurosurgical procedures and the safe and effective therapeutic dose will be at the concentration embedded of 4.167 mg/disc or more of vancomycin.

• KSBB Journal
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• 제21권4호
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• pp.312-316
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• 2006

본 연구에서는 은행잎 추출물의 Staphylococcus aureus에 대한 항균효과를 검증하기 위해 먼저 에탄올 농도별로 bilobalide와 ginkgolide A, B의 성분을 분석한 결과 40% 에탄올 용매를 최적 활성농도로 결정하였다. Disc diffusion test, Optical density test을 통한 S. aureus 항균실험 결과 에탄올 추출농도가 증가할수록 항균효과가 증가하나 40% 에탄올 이상에서는 항균활성에 큰 차이가 없었다. 주사전자현미경을 통하여 은행잎 에탄올 40% 추출물 16배 농축액을 처리한 균의 세포표면을 확인한 결과 심하게 손상되었음을 확인할 수 있었다. 투과전자현미경을 이용하여 관찰한 결과 은행잎 추출물로 처리한 균주에서는 세포벽이 관찰되지 않았으며, 이는 은행잎 추출물의 주성분인 bilobalide와 ginkgolide A, B가 세포벽 합성을 저해하는 것으로 보여진다.